+ equals universal iPhone/iPad app in App Store

If you see a + sign next to or below an app in the iTunes App Store, it indicates that app is universal -- designed to work natively on both the iPhone and iPad.

Typically these universal apps are provided by developers when the functionality is similar on both iPad and iPhone, but due to the iPad's large screen a different interface is needed (to include sidebars, popovers, and wide views instead of deep levels).

It also means you only have to download -- and pay for -- the app once.

Sure, you can run any iPhone app on the iPad if you're okay with boxing or chunky double fuzzy 2x mode, but universal apps ensure you get the best user interface -- and user experience -- possible on all your current iOS devices.

So if you have an iPhone or iPod touch and an iPad, and you see the + sign for a universal app, you're good to go.

I read it somewhere on the app store. But I stumbled upon on it by mistake. It should definitely be more visible for iPad users to notice. Now every time I shop the app store I'm always on the lookout for the little + symbol.

"It also means you only have to download — and pay for — the app once."
Twitterrific wasn't exactly a great example. They have already alienated customers by requiring them to pay twice -- once for Twitterrific Premium, and now again if users want the ad free version.

Tom,
If Apple would allow a way for us to give discounts across different products, we'd gladly have done that for Twitterrific Premium owners. As it was, it's not currently possible. In addition, this is an all new version and lots of work has gone into it. We've not charged an upgrade to Twitterrific for iPhone since version 1 two years ago. The upgrade from 1 to 2 was free. If we gave free upgrades to our products for life, we'd have to stop making software. Thanks for listening.

@Striatic: surprisingly, they look about the same. I am guessing it is because the iPad is not using iOS4, and does not exactly understand the higher resolution resources, and instead just blows up the graphics instead of properly scaling them